Means for connecting electric lines.



L. C. BYGRAVE.

MEANS FOR CONNECTING ELECTRIC HNES.

APPLICATION FILED NOV-22. I916.

Patented June 18, 19%

4 SHEETS-SHEET 1.

L. C. BYGRAVE.

MEANS FOR CONNECTING ELECTRIC LINES.

APPLICATION FILED NOV. 22,19I6.

Patented June 18, I91&

4 SHEETS-SHEET 2.

LQNQ QUSQ L. C. BYGRAVE.

MEANS FOR CONNECTING ELECTRIC LINES.

APPLICATION FILED NOV. 22. 1916.

Patented June 18, 1918..

4 SHEETS-SHEET 3- N L. C. BYGRAVE.

MEANS FOR CONNECTING ELECTRIC LINES.

APPucATmN FILED N0v.22, 1916.

lfifigmwgm Patented June 18, 1918.

4 SHEETSSHEET 4.

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apeciflcation of Letters Patent.

Patented dune lid, Thin" Application tiled ttovcmber Eta-wit. aerial 1t0. Matted ft'o all whom it may concern."

Be it lrnown that l, linonano Guanine Bvenavn, a subject of the lting ofGreat Britain, and a resident or Marconi House, Strand, London, England,have invented a new and usetul lmprovement in Means for ConnectingElectric Lines, of which the tollowing is a specification.

This invention relates to devices, tor establishing connection betweentwo groups of lines, and more particularly to devices in which theconnections are efiected by rela S.

The drawings illustrate the invention as applied to a relay telephonesystem.

vFigure 1 shows a group of lines X having access to a group of outgoinglines T.

Fig. 2 shows a group ot lines having access to a group of outgoing linesand a group of incoming lines.

Fig. 3 shows a group of lines having access to a larger group ofoutgoing lines and a larger group ol incoming lines.

Eig. A shows a modification.

Two wiresA and E are shown as connected up by each relay while a thirdwire R is used for retaining purposes. This is usual in telephone worlr,but it will be readily understood that any required number of wires canhe connected up by each relay. The relays are brought into operation bythe two wires A and B being connected together in accordance withstandard telephone practice, but any other method I could be used.

The lines Y may be multipled to other relay groups.

Each set of wires A, E and lit oil the group i i Y have associated withthem another wire till G, which is sometimes lrnown as the guardingwire, to prevent a calling line obtaining.

connection with an engaged line. This is brought about according to thisinvention by normally having this wire connected to battery anddisconnecting it when the line becomes engaged. This method has severaladvantages over the one generally used, tor

it a fuse ll associated with any line be blown owing to a fault, or itthe test wire be broken for any reason, then that line is renderedinaccessible.

The operation of the circuit shown will now be described in detail. Ttwill be assumed that the line it) has to be connected to a tree line otthe group i the first line 0 being assumed engaged from another relaygroup and a relay T associated with it being therefore energized. @n thewires A and B (L being joined together by the caller lifting hisreceiver or the like, circuit 1 is completed and the line relay 1D-operates. Circuit 2 is completed and relay E operates. This connects theGr wires of all the Y lines to which the group has access to theconnection-determining relays M. The M relays therefore of disengagedlines will operate; those of busy lines will not since the negativepotential will have been removed from their Gr wires by the operation oftheir T relay. M will therefore not be operative, but both M and Moperate as U and U are both disengaged (circuits 3 and A). M v operatingopens the circuits to the springs of M and thereby renders the operationof the latter inefltective, and only circuit 5 ofone connecting relay,via, C is completed. The latter extends the wires of A and B (L to theline and T operates (circuit' 6). Circuit 3 is now brolren,

- rendering the line U inaccessible to any fun ther calling lines, andthe retaining circuit 7 is completed operating the cut-ofl" relay E Thisreleases relays D and E. The connection between the line E and.@ ismaintained so long as the wires A and B are connected together. I

lit the relay group is used in connection with an automatic telephonesystem in which the desired connection is built up by breaking theconnection between the wires A and B a certain number of times, T ismade slow to release and is operated indirectly from the wires A and Ein a well known manner.

Fig. 2 shows one method oil applying the a invention to a relayarrangement in which intermediate lines are used to give access to twogroups of lines, one of which may be used for outgoing and the other torincomingb traflic.

he lines X are particular to the relay group, but the outgoing lines Tand the incoming lines Z may be multipled to any number of relay groups.

The operation will first be described when a line of group X, say T1obtains connection with a tree line of group Y. When the wires A and E(E are connected together by the lilting oil a receiver or the lilre.circuit 1 is completed and D operates. E

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ltltl lhli lllll operates (circuit 2) and connects the G wires of the Ylines to the corresponding M relays, over one winding of the OC relaysand break contacts of the IC relays. The latter contacts'prevent the Mrelays energizing if the corresponding intermediate line is engaged foran incoming connection. As the G wires of free lines only are connectedto battery, an M relay can only energize when the intermediate andoutgoing lines associated with it are both free. Instead of allowing allthe M relays corresponding to disengaged intermediate and outgoing linesto operate and to render only the first one effective (as was shown inFig. 1) only the first M relay is allowed to operate completely owing toeach M relay breaking the circuit of all the M relays above it. By thismeans the number of contacts on the M relays is reduced. It will be seentherefore that only the M relay of the first level with both a freeintermediate line and a free outgoing line will 05- erate. F orinstance, if the outgoing line 1 be engaged, M will not be able tooperate as battery will not be connected to the corresponding G wire. Ifthe second outgoin line be free, but the correspon ing intermediate linehe engaged incoming (in which case the relay 1C will be energized) thecircuit for M will be broken b 16 If the third outgoing line 0 and t ecorresponding intermediate line are both free, then M will operate overcircuit 3, and prevent the operation of M by cutting ofi the commonearth. Circuit a is completed and C operates. The lines A and B (L?) areextended to O and apparatus associated with the latter (similar to the Trelays of Fig. 1) disconnects the negative battery from the G wire andcompletes the retaining circuit 5 and E operates releasing 1D and F.

For an incoming call a similar series of operations takes place. 7 Inthis case the aparatus is not brought into operation by an line calling,for the line is being called by a Z line. A numerical selector or othermeans, not shown, is used to determine the lineto'be called and operatesthe J relay of the group'to which the line belongs, and at the same timeconnects battery to the N wire of the required line. For instance, if Lis to be called, J would be operated and N (L) connected to battery.;.'l;he M relay, say M of the first level which has both a freeintermediate line and a free incoming line, operates. The connectingrelay C operates, and apparatus associated with the incoming line Idisconnects negative battery from ,the'J wire and operates E J isreleased from the selecting apparatus or in any other suitable manner.The wire H, which is earthed bythe M relay, can be used to operateapparatus, for instance, a relay or DC relays.

associated with the corresponding incoming .line, to connect such lineto the line from which the numerical selector has been operated.

()ne method of applying this invention to a relay arrangement is shownin Fig. 3. In this diagram only two lines of the X group and twointermediate lines are shown, though any suitable number maybe used. Twooutgoing (Y) and two incoming (Z) lines are shown as associated witheach intermediate line though the number need not be two. The connectionof the line L to the first free outgoin line will now be described. Onthe lines and B being connected D operates over circuit 1 and F ovencircuit 2. If both the intermediate line and the first outgoing line 0are free 'M and .OC operate over circuit 3. If the intermediate line hadbeen engaged incoming, this circuit would have been broken by 1C or 1C.The operation of 0C prevents the operation of OC and the operation of Mprevents the operation of any other M Circuit 4 is completed and Coperates. E operates as before described, and D and F release. Similaroperations take place when connection between an incoming and a calledline is required, as will be readily understood from the description ofthe operation of Fig. 1.

In the arrangements which have been described no means are provided toprevent double connection. For instance, if the two wires A and B of Lare connected together at the same moment as the two wires A and B of Lboth these lines will be connected to the same outgoing line, To preventthis a suitable resistance can be inserted in each retaining wire at thepoint B (Fig. 1) This resistance would be such that in series with itone connecting relay can retain but not two or more relays in parallel.If two lines call concurrently therefore, both connecting relays willnot be able to hold, and the one releasing first will release thecut-off E, and the line relay D will re-operate to cause the callingline to be connected to the next free outgoing line.

The resistance used for the arrangements shown in Figs. 2 and 3 would besuch that the two connecting relays used for each connection couldretain in series with it, but not two or more sets of connecting relaysin parallel in series with it. 4

A similar arrangement could be used for incoming calls.

The invention has been described in connection with systems whereinseparate wires are used for retaining and guarding purposes. It can bearranged to use one wire for both purposes, as shown in Fig. 4. TheWires R and G are connected in parallel at the point 4 and this commonwire is e22 tended through the back contact of relay T naoonoa tonegative of battery at 3; tor example, it the corresponding line isfree. When relay T is energized, this common circuit is then connectedto earth at 3"; for example, when t the retaining circuit is completed.The coils of the E relays are shown connected to negative battery.

The invention is not limited to the relay arrangements. oncircfiitsshown, as many to modifications can be employed to fulfil otherconditions. What T claim is l. The combination of a group of electricallines, a second group of lines, a conto motion-determining deviceassociated with each of the lines of the second group, means forrendering inoperative the connectiondetermining devices of bus lines andmeans for rendering operative t e connection-deao termining device ofone idle line and one only when a connection is to be'made and thenonly.

2. The combination cl a'group oi electrical lines, a second group oflines, a. number to of connection-determining devices arranged in adefinite order of precedence and associated one with each of the linesof the second group, means for renderin inopera tive theconnection-determining evi'ces of no lousy lines, meanstor renderingthat one of A the connection-determining devices associated with idlelines. which is first in precedence operative when a connection is to bemade and then only and means for prevent to ing the operation of suchconnection-determining devices olc idle lines as are lower in the orderof precedence.

3. The combination of a group of electrical lines, a second group oflines, a number to of connection-determining devices arranged in adefinite order of precedence and associated one with each of the linesof the sec ond group, means for controlling-each device both from itsassociated outgoing line: to and from such devices as have precedenceover it, means for rendering inoperative the connection-determiningdevices of lousy lines and means for rendering that one of theconnection-determining devices associated with to idle lines which isfirst inprecedence operative when? a connection is to be made and thenonly 4. The combination of a group of electrical lines, a group oioutgoing lines, a oup on of incoming lines a connection-determiningdevice associated jointly with one ot the outgoing lines and with one oithe incoming lines, means for rendering the device inoperative wheneither its outgoing or its into coming line isengaged and means forrendering the device operative to connect one oi the first mentioned oupol' lines either to its outgoing or to its incoming line when suchoutgoin and incog lines are idle.

to 5. The com ination ot a group of electrical lines, a group ofoutgoing lines, a group of incoming lines, a plurality-ctconnectiondetermining devices arranged in a definite order of precedenceand each associated jointly with one of the outgoing lines and to withone of the incoming llnes, means for rendering inoperative any devicewhen either its outgoing or incoming line is engaged,

. means for rendering operative the first connection-determining deviceof which both to the outgoing and incoming lines are idle and means forpreventing the operation or such devices as are lower in the order ofprecedence than such first device.

6. The combination of a group of lines, to a source oi current, a groupof outgoing lines, a number of connecting relays each of which isassociated both with a line of the first group and with an outgoingline, a current-connecting relay associated with at each line of thefirst mentioned group and adapted to connect to the source of currentall the connecting relays associated with its line, aconnection-determining relay associated with each outgoing line andadapted to to complete the circuit of any of the connecting relaysassociated with its line, means for rendering inoperative theconnectiondetermining relays of busy outgoing lines and means forrendering operative the conto nection-determining relay of one idleoutgoing line and one only.

7. The combination of a group of lines, a source oi current, a group ofoutgoing lines, of connecting relays each of which is associated with aline of the first group, with an outgoing line and with an incomingline, a current-connecting relay associated with each line ot'thefirst-mentioned group and lot adapted to connect to the source oicurrent all the connecting relays associated with its line, a number ofconnection-determining relays each associated both with an outgoing andwith an incoming line and adapted to no complete the circuit oiany ofthe connecting relays associated with its lines, means for renderinginoperative the connectiondetermining relays of busy outgoing or incoming lines and means for rendering oplit erative theconnection-determining relay oi opp idle outgoing or incoming line andone o y.

' 8. The combination of a group of lines, a source of current, a groupof outgoing lines, are a number of connecting rela s each of which isassociated both with a line oil the first group and with an outgoingline, a currentconnecting relay associated with each line of thefirst-mentioned oup and adapted to lat connect to the source of currentall the connectin relays associated with its line, a number 0Tconnection-determining relays arranged in a definite order oiprecedence, as sociated one with each ot the outgoing lines ran agroup'ot incoming lines, a number ioo &

and adapted to complete the circuit of any of the connecting relaysassociated with its line, means for rendering inoperative theconnection-determining relays of busy outgoing lines, means forrendering operative that one of the connection-determining relaysassociated with idle lines which is first in precedence and means forpreventing the operation of such connection-determining relays of idlelines as are lower in the order of precedence.

9. The combination of a group of lines, a source of current, a group ofoutgoing lines, a group of incoming lines, a number of connecting relayseach of which is associated with a line of the first group, with anoutgoing line and with an incoming line, a current-connecting relayassociated with each line of the first mentioned group and adapted toconnect to the source of current all the connecting relays associatedwith its line, a number of connection-determining relays arranged in adefinite order of precedence, associated one with each of the out- 7Lacaeos going and with one of the incoming lines and adapted to completethe circuit of any of the connecting relays associated with its lines,'-means for rendering inoperative the connection-determining relay of anybusy outgoing or incoming line, means for rendering operative that oneof the connectiondeterminlng relays associated with idle lines which isfirst in precedence and means for preventing the operation of suchconnectiondetermining relays of idle lines as are lower in the order ofprecedence.

10. The combination of a group of electrical lines, a second group oflines, a connection-determining device associated with each of the linesof the second group, and means for momentarily rendering operative theconnection-determining device of one idle line and one only to bringabout a connection.

In testimony that I claim the foregoing as my invention, I have signedmy name this 8th day of December 1916.

LEONARD CHARLES BYGRAVE.

